The expression "1 x 10^4" is a way to represent the number 10,000 using scientific notation. In this format, "1" is the coefficient, and "10^4" indicates that the number 10 is raised to the power of 4, meaning it is multiplied by itself four times: 10 x 10 x 10 x 10. This method simplifies the writing of large numbers. Scientific notation is commonly used in fields like science, engineering, and mathematics to make calculations easier and to express very large or very small numbers succinctly. For example, instead of writing 10,000, one can simply write "1 x 10^4."